Heat conduction membrane, injection molding part and injection molding process

Abstract

According to the embodiment of the invention, the invention provides a heat conduction membrane, an injection molding part and an injection molding process. The heat-conducting membrane comprises a first base layer, a heat-conducting material layer and a second base layer, the first bonding layer is arranged between the first base layer and the heat conduction material layer, and the second bonding layer is arranged between the heat conduction material layer and the second base layer. The injection molding part comprises an injection molding part and a heat conduction membrane coupled to the injection molding part. The preparation process comprises the following steps: membrane bonding: respectively bonding a first membrane and a second membrane on two sides of a heat conduction material through a bonding agent to obtain a membrane prefabricated product; membrane punching: punching and cutting the membrane prefabricated product according to a preset requirement to obtain a heat-conducting membrane; and performing in-mold molding: fixing the heat-conducting membrane in a mold, and performing integral injection molding on the heat-conducting membrane and the molten material to obtain an injection-molded part. Therefore, the heat-conducting property of the injection-molded part can be improved, local high temperature on the surface of the injection-molded part is reduced, and heat dissipation of the injection-molded part is promoted.

Description

Technical Field

[0001] Example embodiments of the present disclosure generally relate to the field of heat dissipation materials, and more particularly to thermally conductive films, injection molded parts, and injection molding processes. Background Art

[0002] At present, in the fields of electrical equipment or electronic devices, injection molded shells are often used to cover internal components. When the electrical equipment (or electronic device) is working, the components inside the electrical equipment generate heat, but due to the shell covering the components and the poor thermal conductivity of the shell, the heat generated by the electrical equipment is not easy to dissipate, so the local temperature inside the electrical equipment is too high. Summary of the invention

[0003] In a first aspect of the present disclosure, a thermally conductive film is provided. The thermally conductive film comprises: a first base layer, a thermally conductive material layer, and a second base layer arranged in sequence; a first adhesive layer arranged between the first base layer and the thermally conductive material layer and suitable for bonding the first base layer and the thermally conductive material layer; and a second adhesive layer arranged between the thermally conductive material layer and the second base layer and suitable for bonding the thermally conductive material layer and the second base layer.

[0004] In some embodiments, the thermally conductive film further includes a connecting strip, which is arranged to at least partially surround the outside of the thermally conductive material layer, and the connecting strip includes: a first connecting portion, which at least partially surrounds the edge of the thermally conductive material layer and is suitable for coupling with the edge of the first base layer; and a second connecting portion, which at least partially surrounds the edge of the thermally conductive material layer and is suitable for coupling with the edge of the second base layer, wherein the first connecting portion and the second connecting portion are coupled together by a first adhesive layer and a second adhesive layer.

[0005] In some embodiments, the width of the connecting strip is 1-3 mm.

[0006] In some embodiments, a plurality of through holes are disposed on the thermal conductive material layer, and the plurality of through holes respectively penetrate the thermal conductive material layer and are suitable for being filled with the first adhesive layer and the second adhesive layer so that the first adhesive layer and the second adhesive layer are bonded to each other.

[0007] In some embodiments, the thickness of the thermally conductive material layer is 0.015 mm-0.075 mm.

[0008] In some embodiments, the thermally conductive film further includes: a display layer coupled to a side of the second base layer facing away from the thermally conductive material layer.

[0009] In some embodiments, the thermally conductive material layer is made of graphene.

[0010] By bonding the first diaphragm and the second diaphragm on both sides of the thermally conductive film respectively, the thermally conductive film can be fixed by the first diaphragm and the second diaphragm. On the one hand, the first diaphragm and the second diaphragm can provide protection for the thermally conductive film, thereby improving the integrity of the thermally conductive film. On the other hand, by injection molding on the surface of the thermally conductive film, the injection molded part is integrally formed on the thermally conductive film, thereby improving the integrity of the graphene film and the injection molded part, so that the thermally conductive film has better thermal conductivity efficiency, thereby also improving the thermal conductivity of the thermally conductive film to the local high temperature in the injection molded part. The local high temperature of the shell is dispersed throughout the shell through the thermally conductive film, thereby accelerating the heat dissipation of the shell.

[0011] In a second aspect of the present disclosure, an injection molded part is provided. The injection molded part comprises: an injection molded part; and a thermal conductive film provided according to the first aspect of the present disclosure, coupled to the injection molded part.

[0012] In some embodiments, the injection-molded part further includes: a third adhesive layer disposed between the thermally conductive film and the injection-molded part.

[0013] In a third aspect of the present disclosure, a process for preparing an injection molded part is provided. The process for preparing the injection molded part includes: film bonding, wherein a first film and a second film are respectively bonded to two sides of a heat conductive material by an adhesive to obtain a film preform; film punching, wherein the film preform is punched and cut according to predetermined requirements to obtain a heat conductive film; and in-mold molding, wherein the heat conductive film is fixed in a mold and integrally injection molded with the molten material to obtain an injection molded part.

[0014] In some embodiments, the preparation process also includes: pretreatment of the first film: applying double-sided tape on the first surface of the first film, and the first surface of the first film is arranged to be the side facing away from the thermal conductive material after the first film is bonded to the thermal conductive material.

[0015] In some embodiments, the preparation process further includes: pretreatment of the second film: coating the display coating on the first surface of the second film, the first surface of the second film being arranged as the side facing away from the thermal conductive material after the second film is bonded to the thermal conductive material.

[0016] In some embodiments, the preparation process further includes: pretreatment of the thermally conductive material: bonding the thermally conductive material to the protective film to obtain a thermally conductive material film, and punching and cutting the thermally conductive material film into a predetermined shape.

[0017] In some embodiments, the injection mode of the in-mold molding is a single-point injection.

[0018] The diaphragm of the part obtained by the one-point injection method is smoother and more beautiful than that of the multi-point injection method. This is because for the multi-point injection method, the molten material is easy to squeeze the diaphragm at the confluence, causing wrinkles on the diaphragm. For the one-point injection method, the molten material can flow steadily on the surface of the diaphragm, thereby reducing the wrinkles of the diaphragm.

[0019] In some embodiments, the gate type for injection molding is a sub-gate.

[0020] In some embodiments, the injection speed during in-mold molding is 20-30 mm / s.

[0021] By controlling the injection speed during injection molding, the molten material can be slowly filled into the mold in a fan shape, further improving the flatness of the diaphragm on the part after injection molding.

[0022] In some embodiments, during IMM, the speed / pressure transition point of injection molding is when the melt fill exceeds 99%.

[0023] By adjusting the speed / pressure conversion point, the flow of the molten material in the mold during the injection molding holding pressure period is reduced, thereby reducing the situation where the diaphragm is squeezed and deformed due to the flow of the molten material.

[0024] In some embodiments, during in-film molding, the temperature of the front mold is 60°C, the temperature of the rear mold is 80°C, and the temperature of the melt is 265°C.

[0025] In some embodiments, the thermally conductive film is fixed to the mold by vacuum adsorption.

[0026] In some embodiments, during in-film molding, the pressure inside the mold is 800-1200 MPa.

[0027] It should be understood that the contents described in this content section are not intended to limit the key features or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, wherein:

[0029] Figure 1 A schematic diagram showing film bonding in the process of an embodiment of the present disclosure is shown;

[0030] Figure 2 A schematic diagram showing the stacking of various layers in the thermally conductive film of an embodiment of the present disclosure; and

[0031] Figure 3A cross-sectional view of a thermally conductive film according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0032] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0033] It should be noted that the titles of any sections / subsections provided herein are not restrictive. Various embodiments are described throughout this article, and any type of embodiment may be included under any section / subsection. In addition, the embodiments described in any section / subsection may be combined in any manner with any other embodiments described in the same section / subsection and / or different sections / subsections.

[0034] In the description of the embodiments of the present disclosure, the term "including" and similar terms should be understood as open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The term "some embodiments" should be understood as "at least some embodiments". Other explicit and implicit definitions may be included below. The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may be included below.

[0035] As briefly mentioned above, the housing of electrical equipment or electronic devices is mostly made of materials such as plastic and through injection molding, which has poor thermal conductivity. As a result, the heat generated by the components in the housing is not easy to dissipate, causing the housing and the internal temperature of the electrical equipment or electronic device to be too high, affecting the normal operation of the electrical equipment or electronic device.

[0036] Since the graphene diaphragm has good thermal conductivity, in some prior arts, the graphene diaphragm is crushed and made into graphene ink, and then the graphene diaphragm is transferred to the surface of the shell in the hope of promoting the heat conduction of the shell and improving the local temperature rise of the shell. However, since the graphene diaphragm exists in the form of powder in the graphene ink, the thermal conductivity of the graphene is greatly affected. Therefore, the method of transferring the graphene ink to the surface of the shell does not significantly improve the local temperature rise of the shell. For example, in the shell of some electronic devices, the shell with the transferred graphene ink can obtain a temperature reduction of less than 5K at the local heating point compared to the shell without the transferred graphene ink.

[0037] Some existing technologies use double-sided tape to directly bond the graphene film to the surface of the housing. However, due to the weak bonding force between the layers inside the graphene film, the double-sided tape fixation method easily leads to delamination of the graphene film, and then part of the graphene film peels off from the delamination, affecting the thermal conductivity of the graphene film.

[0038] The embodiments of the present disclosure propose a thermally conductive film, an injection molded part, and an injection molding process to solve or at least partially solve the above-mentioned problems or other potential problems. According to the embodiments of the present disclosure, by bonding the first film and the second film on both sides of the thermally conductive film, the thermally conductive film can be fixed by the first film and the second film. On the one hand, the first film and the second film can provide protection for the thermally conductive film, thereby improving the integrity of the thermally conductive film. On the other hand, by injection molding on the surface of the thermally conductive film, the injection molded part is integrally formed with the thermally conductive film, thereby improving the integrity of the graphene film and the injection molded part, so that the thermally conductive film has better thermal conductivity efficiency, thereby also improving the thermal conductivity of the thermally conductive film to the local high temperature in the injection molded part. The local high temperature of the outer shell is dispersed throughout the outer shell through the thermally conductive film, thereby accelerating the heat dissipation of the outer shell.

[0039] In some embodiments, for example, in some electrical devices, the housing made of the injection molded parts provided by the present disclosure can achieve a temperature reduction of more than 40K at the local heat generation point compared to traditional heat conduction and heat dissipation technologies.

[0040] According to the thermally conductive film and injection molded parts provided by the embodiments of the present disclosure, generally, the preparation of the injection molded parts includes preparing the thermally conductive film and integrally injection molding the thermally conductive film and the molten material. These two steps will be specifically introduced below.

[0041] The preparation of the thermally conductive film includes the following steps.

[0042] The first film 3 is pre-treated by coating a double-sided adhesive tape on a first surface of the first film 3 .

[0043] The thermally conductive material 61 is pretreated by attaching the thermally conductive material 61 to the protective film 62 to obtain the thermally conductive material film 6, and then the thermally conductive material film 6 is punched (for example, the thermally conductive material film 6 can be punched and cut in a film punching machine), so that the thermally conductive material 61 is at least cut into a predetermined shape.

[0044] In some embodiments, the second film 4 may be pre-processed to coat the display material on the first surface of the second film 4. For example, in some embodiments, the display material may be printed on the second film 4 by screen printing, thereby forming a display layer 108 on one side of the first surface of the second film 4 to display information such as background color, characters, anti-counterfeiting labels, logos, etc. In other embodiments, there may be multiple display materials, and the corresponding display layer 108 may have multiple layers. For example, the display layer 108 may have three layers to display red, green, and blue colors respectively. Thus, by combining the three display layers 108, pattern information can be presented on the surface of the second film 4.

[0045] It should be understood that in the process of preparing the thermally conductive film, the order of pretreatment of the first film 3, the thermally conductive material 61, and the second film 4 is not limited, and the pretreatment of the three materials can be performed sequentially or simultaneously.

[0046] Figure 1 A schematic diagram showing film bonding in the process of the embodiment of the present disclosure is shown, Figure 3 As shown, the preparation of the thermally conductive film also includes film bonding, and the pre-treated first film 3, the thermally conductive material 61, and the second film 4 are bonded to each other through the adhesive 5. Specifically, in some embodiments, a bonding machine can be used to bond the thermally conductive material 61 to the first film 3 and the second film 4. For example, the second film 4 is rolled up and continuously passes through the bonding machine. The bonding machine first coats the adhesive 5 on the second surface of the first film 3 opposite to the first surface, and then attaches the thermally conductive material film 6 to the second surface of the second film 4. During this process, the thermally conductive material 61 attached to the protective film 62 in the thermally conductive material film 6 is bonded to the second surface of the second film 4 by the adhesive 5. Then the bonding machine coats the adhesive 5 again on the side of the thermally conductive material 61 away from the second film 4, and finally bonds the first film 3 to the side of the thermally conductive material 61 away from the second film 4, and makes the second surface of the first film 3 opposite to the first surface face the thermally conductive material 61, thereby obtaining a film preform. The obtained film preform is rolled up at the other end of the laminating machine.

[0047] Finally, the membrane preform is punched and cut in a membrane punching machine according to predetermined requirements to obtain a thermally conductive membrane with specific requirements. Thus, the thermally conductive membrane is prepared.

[0048] Figure 2 A schematic diagram showing the stacking state of each layer of the thermal conductive film of the embodiment of the present disclosure is shown. Figure 3 FIG. 2 shows a cross-sectional view of a thermally conductive film according to an embodiment of the present disclosure. Figure 2 and Figure 3As shown, in the prepared thermally conductive film, the first film 3 is formed as the first base layer 103 of the thermally conductive film, the second film 4 is formed as the second base layer 107 of the thermally conductive film, and the thermally conductive material 61 is formed as the thermally conductive material layer 105 of the thermally conductive film. The two layers of adhesive 5 on both sides of the thermally conductive material 61 are respectively used as the first adhesive layer 104 and the second adhesive layer 106 to respectively bond and fix the first film 3 or the second film 4 to the thermally conductive material 61.

[0049] In some embodiments, the display material coated on the second film 4 is arranged as the display layer 108 on a side of the second base layer 107 facing away from the thermal conductive material layer 105 .

[0050] During the preparation of the thermally conductive film, the thermally conductive material film 6 and the film preform are punched and cut once respectively during the pretreatment of the thermally conductive material 61 and the punching of the film. In the two punching and cutting, the cut shape of the thermally conductive material 61 is similar and smaller than the cut shape of the film preform. That is to say, the projections of the first film 3 and the second film 4 on the plane where the thermally conductive material 61 is located have an edge portion that exceeds the shape of the thermally conductive material 61. The edge portions of the first film 3 and the second film 4 are bonded to each other by the adhesive 5, so that the thermally conductive material 61 is completely wrapped inside the first film 3 and the second film 4.

[0051] like Figure 2 and Figure 3 As shown, for the thermally conductive film, the thermally conductive film further includes a connecting belt, which at least partially surrounds the outer side of the thermally conductive material layer 105 and includes a first connecting portion 201 and a second connecting portion 202. The first connecting portion 201 is coupled to the first base layer 103, and the second connecting portion 202 is coupled to the second base layer 107. The first connecting portion 201 and the second connecting portion 202 are bonded and fixed by the first adhesive layer 104 and the second adhesive layer 106.

[0052] According to the above-mentioned preparation process of the thermal conductive film, the first connection part 201 and the first base layer 103 are obtained by punching and cutting the first film 3, that is, the first connection part 201 and the first base layer 103 are integrally formed. Similarly, the second connection part 202 and the second base layer 107 can also be integrally formed.

[0053] In some other preparation processes, the first connection part 201 and the first base layer 103, and the second connection part 202 and the second base layer 107 may also be coupled together by any appropriate means such as bonding.

[0054] In some embodiments, the width of the thermally conductive film connection band can be controlled between 1 mm and 3 mm to ensure the stability of the coupling between the first connection portion 201 and the second connection portion 202 .

[0055] In some embodiments, when the thermal conductive material 61 is pre-processed, the punching and cutting of the thermal conductive material film 6 also includes opening a plurality of through holes 109 penetrating the thermal conductive material 61 on the thermal conductive material 61. Thus, the thermal conductive material layer 105 of the thermal conductive film has a plurality of through holes 109, and the adhesive 5 of the first adhesive layer 104 and the second adhesive layer 106 can be filled in the through holes 109 and bonded to each other, and then the first base layer 103 and the second base layer 107 can be directly bonded by the adhesive 5 at the position of the through holes 109, further improving the overall strength of the film.

[0056] In some embodiments, the thermal conductive material 61 may be graphene. Since graphene has good thermal conductivity, graphene as the thermal conductive material 61 can effectively improve the local temperature rise of the injection molded part 101. The thickness of the graphene may be 0.015 mm to 0.075 mm. For example, in some embodiments, the thickness of the graphene may be 0.015 mm to 0.019 mm, 0.022 mm to 0.027 mm, 0.030 mm to 0.034 mm, 0.032 mm to 0.042 mm, 0.043 mm to 0.053 mm, 0.065 mm to 0.075 mm, etc.

[0057] In some alternative embodiments, the thermally conductive material 61 may also include any material with good thermal conductivity, such as silver foil and copper foil.

[0058] As mentioned above, the preparation process of injection molded parts also includes the integrated injection molding of the prepared thermal conductive film and the molten material: the prepared thermal conductive film is fixed to the mold by vacuum adsorption, and then the injection molding machine is started. Under the conditions of the front mold temperature of 60°C and the rear mold temperature of 80°C, the molten material at a temperature of 265°C is injected into the mold by a point injection method. During injection molding, the gate type is a submerged gate. During injection molding, the pressure in the mold is controlled to be 800-1200MPa, the injection speed is 20-30mm / s, and the speed / pressure conversion point of injection molding is when the molten material fills the mold to reach or exceed 99% (for example, 99.0%, 99.1%, 99.2%, etc.).

[0059] After the injection molding is completed, the injection molded part 101 is integrally formed on one side of the thermally conductive film to obtain an injection molded part. Since this injection molded part has a stable thermally conductive material layer 105, when it is used as a shell of an electrical device or an electronic device, it can effectively conduct local high temperature to various places, which is beneficial to the heat dissipation of the shell and avoids the situation where the internal ambient temperature of the shell is too high and affects the normal operation of components and instruments.

[0060] The above descriptions of various implementations of the present disclosure are exemplary, non-exhaustive, and not limited to the disclosed implementations. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described implementations. The selection of terms used herein is intended to best explain the principles of the implementations, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the various implementations disclosed herein.

Claims

1. A thermally conductive film, comprising: A first base layer (103), a heat conductive material layer (105) and a second base layer (107) are arranged in sequence; A first adhesive layer (104), arranged between the first base layer (103) and the thermally conductive material layer (105), and adapted to bond the first base layer (103) and the thermally conductive material layer (105); as well as The second adhesive layer (106) is arranged between the thermal conductive material layer (105) and the second base layer (107), and is suitable for bonding the thermal conductive material layer (105) and the second base layer (107).

2. The thermally conductive film according to claim 1, further comprising a connecting belt, arranged to at least partially surround the outer side of the thermally conductive material layer (105), wherein the connecting belt comprises: A first connecting portion (201), at least partially surrounding the edge of the thermal conductive material layer (105), and adapted to be coupled with the edge of the first base layer (103); as well as The second connecting portion (202) at least partially surrounds the edge of the thermal conductive material layer (105) and is suitable for coupling with the edge of the second base layer (107). The first connecting portion (201) and the second connecting portion (202) are coupled together via the first adhesive layer (104) and the second adhesive layer (106). The thermally conductive film according to claim 2 , wherein the width of the connecting band is 1-3 mm.

4. According to the thermally conductive film according to any one of claims 1 to 3, a plurality of through holes (109) are provided on the thermally conductive material layer (105), and the plurality of through holes (109) respectively penetrate the thermally conductive material layer (105) and are suitable for being filled with the first adhesive layer (104) and the second adhesive layer (106) so that the first adhesive layer (104) and the second adhesive layer (106) are bonded to each other.

5. The thermally conductive film according to any one of claims 1 to 3, wherein the thickness of the thermally conductive material layer (105) is 0.015 mm-0.075 mm.

6. The thermally conductive film according to any one of claims 1 to 3, further comprising: The display layer (108) is coupled to the side of the second base layer (107) facing away from the thermal conductive material layer (105).

7. The heat-conducting film according to any one of claims 1 to 3, wherein the heat-conducting material layer (105) is made of graphene.

8. An injection molded part, comprising: Injection molded part (101); as well as The thermally conductive film according to any one of claims 1 to 7 is coupled to the injection molded part (101).

9. The injection molded part according to claim 8, further comprising: A third adhesive layer (102) is arranged between the thermally conductive film and the injection molded part (101).

10. A process for preparing an injection molded part, comprising: Membrane bonding, the first membrane (3) and the second membrane (4) are respectively bonded to two sides of the heat conductive material (61) by means of an adhesive (5) to obtain a membrane preform; Diaphragm punching, punching and cutting the diaphragm preform according to predetermined requirements to obtain a thermally conductive diaphragm; as well as In-mold molding, the thermally conductive film is fixed in a mold and integrally injection-molded with the molten material to obtain an injection-molded part.

11. The preparation process according to claim 10, further comprising: Pretreatment of the first diaphragm (3): applying double-sided adhesive to the first surface of the first diaphragm (3), wherein the first surface of the first diaphragm (3) is arranged to be the side facing away from the thermally conductive material (61) after the first diaphragm (3) is bonded to the thermally conductive material (61).

12. The preparation process according to claim 10, further comprising: Pretreatment of the second film (4): coating the display coating on the first surface of the second film (4), the first surface of the second film (4) being arranged as the side facing away from the heat-conducting material (61) after the second film (4) is bonded to the heat-conducting material (61).

13. The preparation process according to claim 10, further comprising: Pretreatment of the heat-conducting material (61): bonding the heat-conducting material (61) to a protective film (62) to obtain a heat-conducting material film (6), and The heat-conducting material film (6) is punched and cut into a predetermined shape.

14. The preparation process according to any one of claims 10 to 13, wherein the injection mode of the in-mold molding is one-point injection.

15. The preparation process according to any one of claims 10 to 13, wherein the injection speed during the in-mold molding is 20-30 mm / s.

16. The preparation process according to any one of claims 10 to 13, wherein during the in-film molding, the speed / pressure switching point of the injection molding is when the molten material is filled to more than 99%.

17. The preparation process according to any one of claims 10 to 13, wherein during the in-film molding, the front mold temperature is 60°C, the rear mold temperature is 80°C, and the melt temperature is 265°C.

18. The preparation process according to any one of claims 10 to 13, wherein the thermally conductive film is fixed to the mold by vacuum adsorption.

19. The preparation process according to any one of claims 10 to 13, wherein during the in-film molding, the pressure inside the mold is 800-1200 MPa.

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